The leading questions in adult second language acquisition explore what capacities the learner brings to the initial task of language learning, how the second language develops over time, and whether native-like attainment is possible. Recently these questions have been addressed from the perspective of neurolinguistics, allowing a fine-grained characterization of the processes underlying online comprehension in second language learners. Several studies of high-proficiency late learners have reported native-like effects for syntactic processing but we still have little understanding of the constraints on native-like attainment, as many of these studies have investigated properties that are similar in the first and second languages. In addition, studies of very early learners have shown that similarity between the native and target language modulates the emergence of native-like effects, but we still have little understanding of whether it is similarity in the inventory of morphosyntactic features or similarity in the way in which a given morphosyntactic feature is realized in the surface morphology that facilitates acquisition. The present project addresses these outstanding issues, utilizing event-related potentials (ERPs) to examine the processing of gender and number agreement by English-speaking adult learners of Spanish. The first study examines learners at three proficiency levels, investigating both the role of the native language and the role of structural distance between the agreeing elements at different stages of development and examining whether or not native-like attainment is possible when properties differ in the first and second language. The second, longitudinal study, tracks students enrolled in their first year of Spanish in order to examine developmental changes in brain responses at three different points. This study investigates whether learners are sensitive to agreement anomalies at early stages and examines to what extent this sensitivity is modulated by the properties of the native language and the structural distance between the agreeing elements.
In adopting both a cross-sectional and a longitudinal approach, the project examines both the constraints on native-like attainment and the way neurophysiological effects emerge during development, crucially investigating what factors affect development throughout acquisition. The study will thus shed light on the developmental process of adult second language acquisition and will introduce a new framework for investigating the components of the second language that present the biggest challenge throughout different stages of learning, informing pedagogical approaches for adult learners. Furthermore, investigating the nature and scope of adult second language acquisition provides a highly-constrained, hypothesis-driven test case for probing the reorganization of a cognitive system in adulthood. Thus, this approach to examining second language acquisition will provide new insights regarding the nature of brain plasticity more broadly. The project will also serve to train the next generation of linguistics undergraduate and graduate students in the fields of second language acquisition and neurolinguistics.
